基于可信度理论的火电厂水汽化学过程故障诊断模型研究

针对火电厂水汽化学过程中广泛存在着的不确定关系,该文研究并设计了一个基于可信度理论的故障诊断模型。在模型中对知识的表达、推理控制机制的选择、不确定算法的构建等问题做了详细的描述;并改进了规则可信度的设定方法,使该可信度推理更接近于人类专家思维。     

介绍几种新型防水材料及其在工程中的应用

焦油聚氨酯有毒、怕水、抗老化能力差 ,采用无莫卡固化剂 ,可以降低毒性 ,能在潮湿面施工。彩色及沥青焦油聚氨酯可以提高抗老化性能。膨胀焦油聚氨酯可代替膨胀橡皮 ,造价低 ,适用已建成的工程伸缩缝止水处理。水溶性环氧树脂适于有水面施工 ,克服了环氧树脂的缺陷 ,应用范围更加广泛。环氧聚氨酯具有刚中有柔的性能 ,适于特殊工程的处理     

Two types of a passive safety containment for a near future BWR with active and passive safety systems

The paper presents two types of a passive safety containment for a near future BWR. They are named Mark S and Mark X containment. One of their common merits is very low peak pressure at severe accidents without venting the containment atmosphere to the environment. The PCV pressure can be moderated within the design pressure. Another merit is the capability to submerge the PCV and the RPV above the core level. The third merit is robustness against external events such as a large commercial airplane crash. Both the containments have a passive cooling core catcher that has radial cooling channels. The Mark S containment is made of reinforced concrete and applicable to a large power BWR up to 1830 MWe. The Mark X containment has the steel secondary containment and can be cooled by natural circulation of outside air. It can accommodate a medium power BWR up to 1380 MWe. In both cases the plants have active and passive safety systems constituting in-depth hybrid safety (IDHS). The IDHS provides not only hardware diversity between active and passive safety systems but also more importantly diversity of the ultimate heat sinks between the atmosphere and the sea water. Although the plant concept discussed in the paper uses well-established technology, plant performance including economy is innovatively and evolutionally improved. Nothing is new in the hardware but everything is new in the performance.     

Thermal hydraulic behaviors during loss of RHR system at mid-loop operation of Chinese 300 MWe PWR NPP

Thermal hydraulic behavior of nuclear power plant (NPP) is analyzed by using mechanistic computer code for loss of residual heat removal (RHR) system during mid-loop operation of Chinese 300 MWe two-loop pressurized water reactor is presented. In the absence of recovery of RHR or other accident management measures, the reactor core will be uncovered for a long term resulting in core heat-up, degradation and relocation to the lower plenum. The effectiveness of available mitigate measures, such as safety injection system, gravity feed from refueling water storage tank (RWST) and steam generator (SG) reflux-condensation, are investigated. Coolant injection is highly effective in halting the accident progression and make the core recovered. The cooling capability of SG reflux-condensation has a relationship with different availabilities of steam generators and decay heat power. 6 days after shutdown, 2SG operation can keep the water level at mid-line of hot leg. 12 days after shutdown, both 2SG operation and 1SG operation can keep the water level at mid-line of hot leg. The analyses also indicate that the cooling mechanism of safety injection system is more effective than gravity feed from RWST and SG reflux-condensation. Through confirming the success criteria of SG reflux-condensation, time windows can be devided. Then, event trees for loss of RHR system under mid-loop operation are built with considering the analysis results and abnormal procedure.     

水冷反应堆燃料元件的在役检测和处理

水冷反应堆包括轻水堆和重水堆,轻水堆分为压水堆和沸水堆;重水堆分为加压重水堆和加拿大的氘铀堆。国际上把它们归为一类进行研究。本文涉及的破损燃料元件的在役检测和处理包括：反应堆运行时的检测;换料时或换料后的检测;在燃料组件内鉴别破损的燃料棒;燃料组件的监测、拆卸和修复;破损燃料棒拆出后的检测,破损定位与修补。     

压水堆蒸发器水位调节失控跳堆分析及在线诊断调整

分析了核电站引发蒸发器给水控制系统(ARE)水位跳堆的主要原因和薄弱环节,建立了在功率运行状态下进行ARE主阀调节偏差在线调整和旁路阀调节偏差在线调整技术,提出并实施处理方案,解决了压水堆机组在启停过程中水位容易发生失控的技术难题.     

A feasibility assessment of the use of nanofluids to enhance the in-vessel retention capability in light-water reactors

Nanofluids, colloidal dispersions of nanoparticles, exhibit a substantially higher critical heat flux (CHF) compared to water. As such, they could be used to enhance the in-vessel retention (IVR) capability in the severe accident management strategy implemented by certain light-water reactors. It is envisioned that, at normal operating conditions, the nanofluid would be stored in dedicated storage tanks, which, upon actuation, would discharge into the reactor cavity through injection lines. The design of the injection system was explored with risk-informed analyses and computational fluid dynamics. It was determined that the system has a reasonably low failure probability, and that, once injected, the nanofluid would be delivered effectively to the reactor vessel surface within seconds. It was also shown analytically that the increase in decay power removal through the vessel using a nanofluid is about 40%, which could be exploited to provide a higher IVR safety margin or, for a given margin, to enable IVR at higher core power. Finally, the colloidal stability of a candidate alumina-based nanofluid in an IVR environment was experimentally investigated, and it was found that this nanofluid would be stable against dilution, exposure to gamma radiation, and mixing with boric acid and lithium hydroxide, but not tri-sodium phosphate.     

录井资料在识别低电阻率油层中的应用

低电阻率油层因其储层电阻率偏低及测井响应特征不明显,因此用常规方法识别油水层难度较大.地质录井的基本任务是取全取准各项资料、数据,为油气田的勘探和开发提供可靠的第一手资料,录井技术的发展使得其资料得到更广泛的应用.应用实例证明,录井资料在评价、识别低电阻油层中也能起到较好的效果,是识别低阻油层的有效方法之一.     

表面活性剂在特殊油藏原油开采中的一些应用

分析了稠油油藏、低渗透油藏在常规开采中存在的问题和缺陷,讨论了表面活性剂在稠油热采、稠油化学吞吐（冷采）以及低渗透油藏降压增注方面的应用,并对不同应用研究中的关键技术进行了论述。     

油田用选择性堵水剂的研究及应用

以聚丙烯酰胺(HPAM)和木质素磺酸盐(Ga-LS)为主要原料,有机铬类为交联剂,弱碱性物质为pH值调节剂,制得选择性堵水剂。确定了选择性堵水剂的最佳配方:0．8％HPAM 2．0％Ca-LS 0．6％交联剂 0．3％pH调节剂。在此配方下,选择性堵水剂成胶时间为7．5 h,成胶强度大于70 Pa·s。对不同渗透率的岩芯,堵水剂的堵水率大于85％,堵油率小于20％,具有良好的选择性。2003年在大庆油田宋芳屯区块现场施工3口井,累计增油量为580 t,累计降水量为 1 677 t,投入产出比为1:3．56,取得了较好的经济效益。